1. Technical Field
The present invention relates generally to computer-accessible storage devices, and more particularly to a network controller for facilitating access to a storage medium accessible to a host across a network.
2. Background of the Invention
Today, digital multimedia devices, such as set-top boxes, digital versatile disc (DVD) players, and high-definition television (HD-TVs), are becoming increasingly popular. These devices typically require storage and manipulation of multimedia comprising large amounts of data. Further, such storage and manipulation often occurs in a home setting. Therefore, research to create a suitable, efficient architecture for high volume storage targeted for home applications is increasingly common. Although many high volume storage devices such as hard disk drives and DVDs are widely used in a personal computing environment, mere high storage volume is not enough in the home network environment.
To appreciate the true advantages of a home network, storage devices (or storage media) otherwise dedicated solely to one application may be shared among multiple systems, and many different applications, across a network. However, it often is difficult to share storage media efficiently and conveniently because many existing storage media are designed for use inside a computing system or host. For example, to play an HD-TV program at a computer lacking a HD-TV tuner card, the program typically must be demodulated in a set-top box and saved to the hard disk drive inside the set-top box. Next, it must be copied to the storage medium in the computer and played at the computer display. Copying of large files or programs may be inconvenient. Additionally, in a home network environment, copying necessarily duplicates content and thus wastes storage capacity. One approach to address these problems is to allow symmetric access to storage media's contents by participating application devices. For example, a set-top box may directly save a recorded program in a network storage medium, which may permit a computer to directly access the stored program for viewing. In such an approach, the network interface to the storage medium and/or application devices (such as a host) should be designed to efficiently utilize home multimedia devices.
Additionally, consumer electronics often are sold at a relatively low price. Furthermore, rapid technology advancements, combined with rapid growth of available contents, means consumer electronics are often supplemented with cheaper, faster, or more efficient devices. Many people, for example, supplement a compact disk player with a digital music player. Thus, low cost is one exemplary consideration for consumers purchasing home network devices. Another exemplary consideration for many consumers is whether a home network device offers sufficient performance to support multimedia applications requiring large amounts of bandwidth. Ideally, the performance of the network storage device should be limited only by the performance of the storage medium itself. That is, the network device controller should perform like a local input/output (I/O) device controller, and the storage medium should be able to yield performance comparable to that of a locally connected storage.
Although there have been many network storage devices, most (if not all) are not well suited for application in home networks. A network file server, the most widely used network storage, may be too expensive for home use. Although in some cases a network file server has been designed using an embedded processor for the purpose of reducing an implementation cost, such servers typically do not offer sufficient performance to support multimedia applications. Rather, a bottleneck is imposed by software processing of the critical network protocol. Such servers are mainly focused on maximizing the performance of a bank of storage media. By contrast, Universal Serial Bus (USB) mass storage media may be offered at a low cost for end users and thus is a candidate for home network storage. However, it is often difficult for a USB mass storage medium to be shared among multiple devices because a USB network is inherently limited to a single host.
Accordingly, there is a need in the art for an improved storage medium directly accessible to a host connected to the storage medium across a network.